When I researched the exit node for the tor circuit I was given, I saw that it was a forum spammer. Even after changing my identity , the new exit node was still listed as a forum spammer. Is this common with tor or dangerous ? I was using the Tor browser for linux.
Tor relays which allow exiting can be used for forum spamming, as such they are often added to generic "blacklists" regardless of any actual abuse having occurred.
This is just the nature of blacklisting and it's not dangerous to you personally while using Tor, however you may find it inconvenient. This is the price of anonymity, you are indistinguishable from spammers (without further verification, e.g. a captcha-based solution).